Dynamic random-access memory (DRAM) integrated circuits, for example, are commonly used for storing data in a digital computer. Currently available DRAMs may contain over 16 million memory cells fabricated on a single crystal silicon chip, each memory cell generally comprising a single transistor connected to a miniature capacitor. In operation, each capacitor may be individually charged or discharged in order to "store" one bit on information. A DRAM is dynamic in the sense that charged memory cells must be refreshed, or recharged, periodically to maintain data integrity; otherwise, charged memory cells may quickly (generally in a fraction of a second) discharge through leakage to a point where they no longer appear to be set to the charged state.
To facilitate construction of 64 Mbit, 256 Mbit, 1 Gbit, and larger DRAMs with correspondingly smaller memory cells, capacitor structures and materials which can store the necessary charge in less chip space are needed; one of the most promising avenues of research is in the area of high dielectric constant materials (defined herein as having dielectric constants greater than 50). Lead zirconate titanate (PZT), barium titanate, strontium titanate, and barium strontium titanate are some common examples of such materials. It is desirable that such a material, if used for DRAMs and other microelectronics applications, be formable over an electrode and underlying structure (without significant harm to either), have low leakage current characteristics and long dielectric lifetime, and, for most applications, possess a high dielectric constant at frequencies of hundreds of MHz up to several GHz.